ratman Posted March 31, 2008 Report Share Posted March 31, 2008 just wondering if there is a way to tell what kind of porting job has been done to banshee jugs, or what kind of combination it would work with,....or a correct way to check port timing?......compression test? thanks for any info on this subject Quote Link to comment Share on other sites More sharing options...
dajogejr Posted March 31, 2008 Report Share Posted March 31, 2008 That is a very, very open ended question. Yes...you can measure porting based on shape, size and timings on them. By timings, I mean when the port opens and closes in relation to the piston travel. Based on that...builders can tailor a motor for you. Beyond that, it's builder's personal preference...and rarely will two builders agree on one single thing. It's what's worked for them in their experience... Quote Link to comment Share on other sites More sharing options...
ratman Posted March 31, 2008 Author Report Share Posted March 31, 2008 ok thanks, is a compressoin test a valid way to show that a porting job should work ok? ive got a set of jugs that were professionally ported at a reputable builder, compareing them to others, they are just mildly done, i want to put them on a 4mm long rod motor and kind of curious as to tell how well the port job will match up? Very tough to tell im guessing, thanks again for info Quote Link to comment Share on other sites More sharing options...
Washburn Posted March 31, 2008 Report Share Posted March 31, 2008 If you get a 4mil longrod you will need A. porting to match the the stroke to get the most out of it and you will need Wiesco 795 series pistons and stroker cut domes or run a spacer plate. Compression doesnt vary a huge amount from a ported and slightly ported motor. You compression should be around 120(stock)-190 with no more than a 5psi diffrence in both cyls, if you have a coolhead with smaller domes or a cut stock head for higher compression. advanced timing raises compression too. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted April 5, 2008 Report Share Posted April 5, 2008 I'm pretty damn sure advanced timing does not raise compression advanced timing raises compression too. As far as your porting goes the only way to determine the type of port and what mods will suit it best is to measure the port timing with a degree wheel (you can also measure the distance from the top of the exhaust port and transfer ports to the deck). Also, like said above the best way to set up a 4mil is to port for the stroke... if your cylinders have already been ported then there is a possibility that they wont be able to be cut for a longer stroke because the port duration may be too much when the material is removed from the port floors. Again, you need to measure them to be sure. Quote Link to comment Share on other sites More sharing options...
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